[Buildroot] mdev

Marcel korgull at home.nl
Mon May 10 20:56:47 UTC 2010

Hi Peter,

Thanks for your reply.  I checked out devtmpfs and will try that. It looks 

For some reason assigning a fixed major to my devices stopped working. I still 
used this with the 2.6.28 kernel but now with the 2.6.33 it just won't work.
Perhaps I missed something to why this doesn't work.

Best regards,

> >>>>> "Marcel" == Marcel  <korgull at home.nl> writes:
>  Marcel> Hi,
>  Marcel> I'm trying to create a couple of device nodes in /dev and
>  Marcel> somehow doing this manually seems not preferred so I'm trying
>  Marcel> to do this via mdev.
>  Marcel> My first question is whether I'm on the right track by using mdev?
> Yes, that's certainly an OK approach. For an even easier setup have a
> look at devtmpfs in the kernel.
>  Marcel> I tried mdev but I can't make it work. Probably this is because
>  Marcel> I have something wrong in either the startup code , the
>  Marcel> mdev.conf file or whatever.  Second I wonder how mdev works
>  Marcel> because I think it needs MAKEDEV or something else) which I may
>  Marcel> be missing and can't find in my buildroot. mknod is on my
>  Marcel> system though.  mdev -s starts and returns after a second or
>  Marcel> so, I see no errors and no other feedback.
> Ok, good. To generate device nodes at runtime you then need tell the
> kernel to use mdev as the hotplug agent. See
> target/generic/target_busybox_skeleton/etc/inittab for an example of a
> working setup.
>  Marcel> I am looking for an example that works with spidev. My guess is
>  Marcel> that the entry in mdev.conf should be something like :
>  Marcel> spidev 0:153 0660
> In general you only need entries in mdev.conf if you need special
> handling (non-standard permissions or scripts executed).
>  Marcel> Would my kernel need hotplug enabled ? (I guess it does).
> Yes.

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